The 1,4-benzodiazepine 4-oxides: 7-chloro-2-methylamino-5-phenyl-3H-1,4 -benzodiazepine 4-oxide (chlorodiazepoxide) and 7-chloro-1,3-dihydro-1-methyl-5 -phenyl-2H-1,4-benzodiazepin-2-one (diazepam); have found wide clinical acceptance in the treatment of psychoneurotic states manifested by tension, anxiety, apprehension, fatigue, depression, agitation and acute alcohol withdrawal. The preparation of these compounds and intermediates therefor are described, for example, in U.S. Pat. Nos. 2,893,992; 3,311,612; 3,446,806; 3,340,253; 3,102,116; 3,109,843 and 3,136,815.